Automatic, Automatical, a.
Etymology: [Cf. F. automatique. See Automaton.]
1. Having an inherent power of action or motion. Nothing can be said to be automatic. Sir H. Davy.
2. Pertaining to, or produced by, an automaton; of the nature of an automaton; self-acting or self-regulating under fixed conditions; -- esp. applied to machinery or devices in which certain things formerly or usually done by hand are done by the machine or device itself; as, the automatic feed of a lathe; automatic gas lighting; an automatic engine or switch; an automatic mouse.
3. Not voluntary; not depending on the will; mechanical; as, automatic movements or functions. Unconscious or automatic reasoning. H. Spenser. Automatic arts, such economic arts or manufacture as are carried on by self-acting machinery. Ure.
Shades of meaning
Fernald has no entry of its own for automatic; he lists it under spontaneous.
Where he writes about it:
In physiology the action of the heart and lungs is called involuntary; the growth of the hair and nails is spontaneous; the action of swallowing is voluntary up to a certain point, beyond which it becomes involuntary or automatic. — from spontaneous